1. Field of the Invention
The present invention relates to equipment used to manufacture ophthalmic devices, and, in particular, to equipment used to manufacture contact lenses.
2. Description of Related Art
Soft hydrogel contact lenses have increased in popularity since they were first introduced in the 1970s. Such contact lenses are conventionally formed through a process in which the material used to make the lenses is placed between two halves of a casting mold, and the entire assembly is then cured to form the desired contact lens shape. After the curing process, the lens is removed from the casting mold and is immersed in a series of fluids to remove impurities therefrom. While still immersed in fluid, the lens is taken to an examination station where it is inspected for foreign particles, holes, and/or deformations caused by the manufacturing process.
Existing systems for the inspection of contact lenses typically include a lens transportation device, a camera, a viewing monitor, and a computer. The computer is configured to run lens examination software which controls the camera during a lens inspection process. In examining the lens, the camera and, in particular, the software, can inspect the lens surfaces for the foreign particles, holes, and deformities discussed above, and the software can control the inspection system to reject a lens if such deformities are found thereon.
Although existing inspection systems have some utility in a contact lens production environment, reliance on such systems can result in a large number of false lens rejections during production. For example, the camera and, in particular, the camera software can not be capable of distinguishing a hole, a foreign particle, or other lens deformities from gas bubbles that have adhered to the surface of the lens. Bubbles can be formed by, for example, turbulent working fluid 42 flow within the various systems used for impurity removal. In such systems, air and other gases can become entrained within the working fluid 42 and high fluid pressures can not allow the entrained air to expand and escape from the working fluid 42. Depending on the type of contact lens being examined and the throughput of the manufacturing line, false lens rejections caused by existing camera inspection systems can dramatically increase production costs and can severely hinder manufacturing efficiency.
Accordingly, the disclosed systems and methods are directed towards overcoming one or more of the problems set forth above.